Which of the following $3 d -m e t a l$ ion will give the lowest enthalpy of hydration $(\Delta_{ hyd } H )$ when dissolved in water?
$Cr ^{2+}$
$Mn ^{2+}$
$Fe ^{2+}$
$Co ^{2+}$
For the following Assertion and Reason, the correct option is
Assertion : For hydrogenation reactions, the catalytic activity increases from Group $5$ to Group $11$ metals with maximum activity shown by Group $7-9$ elements.
Reason : The reactants are most strongly adsorbed on group $7-9 $ elements.
The spin only magnetic moments (in $BM$) for free $\mathrm{Ti}^{3+}, \mathrm{V}^{2+}$ and $\mathrm{Sc}^{3+}$ ions respectively are (At.No. $Sc: 21; Ti : 22; V : 23)$
Which of the following statements is incorrect?
Which of the following have highest melting point
Electrons in a paramagnetic compound are